Deciphering the genetic basis of tocopherol biosynthesis in almond kernel
Almond is one of the most important tree nut crops because of its high nutritive value, namely in lipids and tocopherol, and its production in Portugal has been increasing in the last years. Tocopherol is an antioxidant that prevents unsaturated fatty acids from peroxidation, hence increasing almond storage life. Genes involved in its biosynthesis have been identified in other species, but no studies have been made in almond. In this study, we aimed to analyse the tocopherol profile by HPLC, and the differential expression levels of candidate genes VTE1, VTE2 and VTE4, involved in tocopherol biosynthesis, by RT-qPCR in ripe fruits of traditional (Gama, João Dias, Fura Sacos and Bonita S. Brás) and commercial (Soleta) cultivars. We found that Fura Sacos was the cultivar with higher α-tocopherol content, while Soleta presented the higher γ-tocopherol content. The VTE4 gene involved in the final stage of α-tocopherol synthesis, the most representative tocopherol isoform in almonds, was the most expressed gene in the ripe fruits analysed. VTE2, with a lower level of mRNA abundance in this study, was involved only in the tocopherol biosynthesis, while VTE1 and VTE4 were involved in both tocopherol and tocotrienol biosynthesis pathways. Since tocopherol is an important parameter in terms of almond quality, further studies are needed to better understand its metabolic pathway and to select cultivars with improved tocopherol contents.
Almeida, G., Faustino, A., Pires, R.C., Soldado, D., Cachucho, L., Oliveira, M.M., Jerónimo, E. and Marum, L. (2023). Deciphering the genetic basis of tocopherol biosynthesis in almond kernel. Acta Hortic. 1362, 397-402
Prunus dulcis, mature kernel, gene expression, vitamin E, antioxidant